SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '136e19f8d12c0348ff702d4d08bd966faf08bdfcd9f8c8e8962f6f064adf34e3' 
  AND token = 'g0cEkT9N1McNit3Mq5NGx6U5+vMIsrN6XT5LcCaldOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}